<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        //第一遍
        function laojiang(a,b=1){
            console.log(a+b);
        }
        laojiang(1);//2
        //第二遍
        function laojiang(a,b=1){
            console.log(a+b);
        }
        laojiang(1);//2
        //第三遍
        function laojiang(a,b=1){
            console.log(a+b);
        }
        laojiang(1);//2
    </script>
</body>
</html>